Reclosable bags are very common, especially in the food industry. Such bags are typically made to be reclosable via the use of a reclosable feature such as a reclosable zipper along the mouth end of the bags. Such zippers can be opened and closed either by digital pressure or by the use of a slider mounted to the zipper.
A bottom-gusseted bag has the advantages that the bag can accommodate a greater volume of product than non-gusseted bags and will stand upright when it is filled. Gusseted bags, however, are more difficult to produce. For example, one method to form a bottom-gusset requires a folding board and a tucking board. Then, a sheet of thermoplastic film is pulled by rollers over the folding board and the tucking board is used to fold the film about a tip of the tucking board. These steps require designing a complicated manufacturing process.
Reclosable bags are a great convenience to users. However, previous reclosable bags could generally be easily tampered with prior to purchase by the user. Consequently, tamper evident features were added to the mouth end of such bags so that a user would know if the bags were tampered with prior to their being used by the user. However, bottom-gusseted bags with reclosable, tamper evident tops are especially difficult to produce. For example, a previous method of forming a bottom-gusseted tamper evident bag requires enclosing the reclosable mouth of the bag in a pocket. This pocket provides the bag with a tamper evident feature, i.e., the reclosable bag top can not be opened without puncturing the pocket or tearing a removable strip on the pocket. Forming a bottom-gusseted bag with a tamper evident pocket, however, requires additional steps that further complicate the manufacturing process.
In order to provide a tamper evident feature, reclosable bags must be filled without destroying the tamper evident feature of the bag. Therefore, bottom-filled, tamper evident reclosable bags were devised. An example of such a bag is proposed in U.S. Pat. Nos. 5,417,040 and 5,529,394. These prior bottom-filled, tamper evident reclosable bags use a top pocket to enclose the zippered mouth of the bag. This top pocket presents a problem, however, if it is desirable to provide a slider to facilitate opening and closing the bag. Specifically, the top pocket prevents a slider from being easily installed on the zipper of prior bottom-filled, tamper evident reclosable bags.
A need therefore exists for a bottom-filled, bottom-gusseted bag that is easy to manufacture and can accommodate a slider for easily opening and closing the bag.